Field of the Invention
The invention concerns elastic exercise cord, more exactly the construction of a connecting device of elastic exercise cord with straps.
Description of the Related Art
There exist exercise equipment for training with elastic exercise cord shown schematically in FIG. 1. In FIG. 2 is then presented one of variant how to use such equipment.
Such elastic exercise cord of an elderly type is known from document U.S. Pat. No. 5,205,803 B1. Cord is made as elastic full cord without any cavity in its center and is provided on both ends with a strap in the form of a loop. In the inner part of strap, which is covered by the sleeve member, an eye from the strap is made, through which the end of the cord is passed-through. Then the end of the cord is bent and fast attached again to the cord and so a joint is created. Nevertheless the eye from the strap is not tough enough and creating the eye is complicated.
Such elastic exercise cord 1 is known from document U.S. Pat. No. 6,202,263 B1. Cord 1 is made of an elastic tubing core 2, which is made as an elastic hollow hose provided on both ends with a strap 3 in the form of a loop. The elastic tubing core 2 is provided by a sleeve member 4 in the form of the longitudinal collapsible hollow sleeve or a tube, which is on its ends tightly fastened to elastic tubing core 2 or the straps 3.
In FIG. 2 one of variant how to train with such elastic exercise cord 1 is shown. It can be seen, how the cord 1 is griped by the strap 3 by person. And particularly the connection between the tubing core 2 and the strap 3 is the subject of the invention. This area is indicated as D in FIG. 1
In the above mentioned document U.S. Pat. No. 6,202,263 B1 several types of connecting devices of elastic exercise cord with the straps are presented. Part of them is based on the principle, where a knot from the tubing core is made and thereby the core is fixed on a steel attachment members with hooks, by which the straps are fixed. In other embodiments the knot is substituted by a ball fixed in the hollow hose of the tubing core, which creates an analogy to the knot. This fixation is not safe and in consequence of possible defect of material the strap could be torn off. In one embodiment is the connection made by an eye, which has a protrusion, which is fixed in the cavity of the hollow hose of the tubing core and the strap is pulled through this eye. Although the eye fixes the strap securely, the fixation of the eye is the cavity of the tubing core is not stable.